1. Field of The Invention PA1 2. Description of The Background Art
The present invention relates generally to a control system for an actuator applicable to a servo system in which an actuator is used together with a low resolution sensor or a speed-reduction gear mechanism having a play.
A Japanese paper titled "Robust Control for Automotive Actuator" which is announced in a "tenth adaptive control symposium" (held from Jan. 31, 1990 to Feb. 2, 1990 in Tokyo, Japan) exemplifies a previously proposed actuator control system.
In the disclosed actuator control system, a method of controlling the actuator of a DC motor type four rear tire wheel steering actuator includes a model adaptive control to which a robust compensator is added.
Therefore, this method can achieve a rear tire wheel steering angle control system having a technique of preventing an influence of dynamics which cannot be modeled and preventing a deterioration of control achievement due to a disturbance.
However, since in the previously proposed actuator controlling apparatus, a resolution of a rotation angle sensor for the DC motor is coarse or low and a play such as a backlash of a gear of a speed-reduction mechanism is present, and a limit cycle occurs at points in the proximity to a target value, the DC motor generates vibrations and vibration sounds and the current flowing through the DC motor always is consumed in a form of rectangular wave. Consequently, the generation of electrical noise and wasteful power consumption are brought out.